Oven-thermo meter



I (No Modql.)

A. P. HARLAND. OVEN THERMOMETBR.

No. 555,697. Patented Mar. 3, 1896.

UNITED STATES ATENT OFFICE.

ALLEN P. HARLAND, OF FLORENCE, ALABAMA.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 555,697, dated March 3,1896.

Application filed August 2 1895.

1-0 aZZ whom it may concern:

Be it known that I, ALLEN P. HARLAND, a

citizen of the United States, residing in Flor- ,ence, in the county ofLauderdale and State of Alabama, have invented certain new and patentedfor indicating the internal temperature of-ovens, but none of them, sofar as I am aware, have come into use to any considerable extent. Theyhave not recommended themselves either to the manufacturer or to thebuyer, because in the first place they have been burdened with too greata multiplicity and complexity of parts, which not only renders themexpensive to manufacture but also causes them to be viewed with disfavorby the ordinary housewife or servant. In the second place, deviceshitherto constructed for this purpose have been provided with partssuchas dials, pointers, and the likeprojecting beyond the surface of thestove or oven. This entails additional work to keep the stove bright andclean and the projecting parts are in the way and are liable to bebroken off or injured.

My invention therefore has been devised for the purpose of providing anoven-thermometer in which the number of parts shall be reduced andsimplified, and the cost of manufacture correspondingly lessened, andalso one in which there shall be no parts projecting outside the surfaceof the oven.

My invention therefore consists in the construction, combination, andarrangement of the parts devised for the above ends, hereinafter fullyspecified, and particularly pointed out in the claims.

Referring to the drawings, Figure l is a front view of an oven-doorprovided with my improved device. Fig. 2 is a rear view. Fig. 3 is afront view of the indicator. Fig. 4 is a section taken on the line 4 4of Fig. 2, and Figs. 5 to 10 represent diagrammatically a series ofsignals or pictures presented at the opening in the stove-door by theindicator in Serial No. '7,947. N0 m del.)

its very varying positions corresponding to changes of internaltemperature.

Referring to the drawings, 1 represents an oven-door provided with anopening 2.

3 denotes a bar which is pivoted at one end 4 to the inside of theoven-door, and which consists of a piece of metal very sensitive tochanges in temperature. The other end of this bar is pivoted at 6 on theindicator-bar 7, pivoted on the oven-door at 8, and carrying at its endthe plate or indicator 9, which normally covers the opening 2 in theoven-door.

In order to hold the plate or indicator 9 up against the opening 2, Iprovide a guide-strip 10, which is secured upon the side of the door soas to press upon the bar 7.

The plate or indicator 9 is made considerably larger than the opening 2,so that only a small portion of the indicator shows at the opening, andthus by observing the proportionate amounts disclosed of two or morecontrasting colors upon the face of the indicator, the heat of theinterior of the oven may be ascertained at a glance withsufficientaccuracy for practical purposes.

I have found the arrangement of contrasting colors which is illustratedin the accompanying drawings to be very convenient in practice. In Fig.3 the face of the indicator is shown as covered with two contrastingcolors, as blue and red. In the normal position, as shown in Figs. 1 and5, the line of demarcation between the two colors will extend diagonallyacross the opening in the oven-door. As the temperature increases, thebar 3 expands, moving'on its pivot 8 the indicatorbar, and so carryingthe indicator across the opening 2. Thus as the heat increases, more andmore of one of the colors, as red, appears at the opening, indicating tothe operator the heat of the oven as observed from previous experience.

It is desirable that the distinguishing marks upon the face of theindicator, as they are seen through the opening in the oven door, shouldbe broad and large, so as to be easily recognizable at a glance withoutclose inspection, and inasmuch as the device will often be used byignorant and illiterate persons it will be found that a series of two ormore contrasting-colors will be more satisfactory than a number offigures or words indicating the actual temperature of the oven. The se'lection of signs to be placed upon the face of the indicator is,however, purely arbitrary.

Should the heat become excessive, the indicator will be moved thereby tosuch an extent as to permit air to pass through the opening 2, if thelatter is left unglazed as I have shown it, and the indicator will thusact as a valve to reduce the temperature within the desired limits.

The opening 2 may be formed in the ovendoor at the time of casting thesame, so that it will be seen that my improved device is extremelysimple and inexpensive. Moreover there are no projecting parts liable toget in the way of the operator. There is no additional labor entailed inkeeping the stove bright and clean, and the appearance of thecontrasting colors at the opening 2 somewhat enhances the attractivenessof the stove.

\Vhile I have shown my device as applied to a door of the oven, which Ihave found in practice to be preferable, it is evident that theapparatus may also be applied to any other of the outer sides of theoven, as desired.

An important advantage which I have had in mind in devising a simple,economical, and commercially successful oven -thermon1eter has been soto construct the apparatus that it could be applied to all existingforms of stoves and ovens without changing the patterns of the oven-dooror the part to which it is to be applied. l\[anufacturers will notregard favorably the introduction of a new device when it entails acomplete change in their existing pat terns and the large outlay ofcapital consequent thereupon. It is readily seen that my improved devicemeets this requirement of economy, the only change in the casting beingthe formation of the opening 2 in the ovendoor. This is readily effectedby placing a suitable core in the mold without any change of thepattern. In this respect I believe my invention to be superior todevices of a similar character hitherto provided, as all prior devices,so far as I am aware, entail a change of the pattern of the oven-door orother part to which the thermometric apparatus is to be applied.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

1. The combination with a side of an oven or other heated chamber, saidside having an opening 2, of an indicator adapted to completely coversaid opening moving across said opening and provided with adistinguishing mark appearing through said opening when covered by saidindicator as aforesaid and serving by its position relatively to saidopen ing to indicate the internal heat of the oven, and operative meanswhereby a change of temperature of the oven communicates said motion tosaid indicator.

2. The combination with a side of an oven or other heated chamber, saidside having an opening 2, of an indicator adapted to completely coversaid opening moving across said opening, provided with contrastingcolors, the aspect of which at said opening when covered as aforesaidserves by their relative proportion to indicate the internal heat of theoven, and operative means whereby a change of temperature of the ovenconnnunicates said motion to said indicator.

The combination with a side of an oven or otherheated chamber, said sidehaving an aperture, of an indicator moving across said aperture andnormally closing it against the admission of air, said indicator alsoacting as a valve or regulator to admit air in the extreme portion ofits travel, said indicator being provided with a distinguishing markappearing through said opening when closed as aforesaid, and serving byits position relatively to said aperture to indicate the internal heatof the oven, and operative means whereby a change of temperature of theoven communicates said motion to said indicator.

In witness whereof I hereunto set my hand in the presence of twowitnesses.

ALLEN P. IIARLAND.

Witnesses:

FRANCIS M. WRIGHT, O. F. J oHNsoN.

